Conventionally, a flow rate adjusting device is known which is used in a fluid supply line in cases such as when mixing multiple chemicals together or accurately adjusting flow rate of demineralized water, etc. used in a manufacturing process of products, and which is also commonly called a regulator. Examples of the flow rate adjusting device used for such purposes include one with a configuration disclosed in Patent Literature 1 below.
Some of these flow rate adjusting devices include a slow-leaking mechanism which secures minute opening in a fully-closed state. In order to enable the adjustment of the minute opening of a valve mechanism for different purposes, the slow-leaking mechanism includes a stroke adjusting mechanism. This stroke adjusting mechanism is, for example, configured to be able to appropriately adjust a protrusion amount of a valve stem, etc. which actuates a valve body in an opening direction.
Further, the aforementioned stroke adjusting mechanism includes a stopper mechanism which fixes an adjusting position so as to prevent the set adjusting position from shifting. Typically, this stopper mechanism has a structure of a double-nut system, for example, which is screwed to an upper end of the valve stem.